Various types of hand operated trucks, barrows, dollys or other wheeled vehicles are known for assistance in moving loads from one place to another. Some of the these vehicles have included special construction features to assist in loading the vehicle from ground level. One reason for doing this is when there is a very heavy load to be transported, effort is required to hoist it to the level of a transport platform or frame. Another reason for ground level loading exists in the case of a trash bin or collector where bulky or heavy material is gathered or swept into one end of a container, which must then be lifted onto a barrow or truck.
One prior art type of conveyance is a sackbarrow which is an L-shaped frame having a pair of wheels at the intersection of the L-shaped frame. One end of the frame terminates in handles. At the other end of the frame is a short loading platform resting at ground level. The load is transported by working the short loading platform beneath the load and then tilting the sackbarrow back on the wheels. Care is required to lift the load on the short loading platform without tipping the sackbarrow back onto the operator.
A variation of the sackbarrow is shown in U.S. Pat. No. 863,275, issued Aug. 13, 1907 to Haffey, wherein a separate wheel carriage is provided, which is supported on legs pivotably connected to the frame. The wheel carriage may thus be swung into a transporting position at the intersection of the L-shaped frame after the load is in position. The arrangement shown does not solve the problem of balancing the load with the possible danger of tipping toward the operator. Also there is no leverage provided for raising the load and hence the loading platform must be kept very short.
Another prior art wheeled vehicle for transport of open trays, boxes or other containers is shown in U.S. Pat. No. 2,374,982, issued May 1, 1945 to Davies. In this device, a modified sackbarrow with a fairly long front loading platform is provided with a supplementary loading platform which hooks to the frame for transporting and assists in loading and unloading. The supplementary platform acts as a load bearing member supported at one end by detachable hooks.
Another wheeled mechanism is shown in U.S. Pat. No. 4,756,540, issued to Crawford on Jul. 12, 1988, in which a wheel carriage is mounted at one end of a U-shaped frame, with an operating handle connected to the other end. A short ground level loading platform is supported on a pair of legs which are pivotably attached to the U-shaped frame. A cross member allows limited pivoting movement of the loading platform.
Other wheeled vehicles suitable for ground level loading are shown in U.S. Pat. No. 87,939 issued Mar. 16, 1869 to Ingraham, U.S. Pat. No. 2,096,994 issued Oct. 26, 1937 to Millen and U.S. Pat. No. 4,735,424 issued Apr. 5, 1988 to Stelter.
While the foregoing devices known in the prior art have facilitated ground level loading, they still have the problem of providing a simple means for placing the wheel carriage directly under the load for ease of balance and transporting, and in facilitating both the lifting of heavy objects, as well as collecting bulky materials at ground level.
Accordingly, one object of the present invention is to provide an improved convertible transport dolly or barrow adapted for loading heavy objects or bulky material at ground level, and then transporting them to another location.
Another object of the invention is to provide an improved and simplified wheeled vehicle adapted for ground level loading and transporting heavy objects employing wheels located directly beneath the center of gravity of the load.